Highland Flat is located in the Ochoco National Forest, approx 15 miles north of Priveville.  In April 2019 I completed a first-time activation of the summit which is suprising since there's very good forest road access up to near the activation zone.  My activation was more challanging due to snow which resulted in a 4-mile snowshoe hike.  But this is usually an easy 4-pointer and recommended for anyone visiting the Prineville area.